My cat has been itching an awful lot and is losing chuncks of hair on her neck, she has several sores now with scabs due to itching so much, what could be causing this?

Fleas, parasites, anxiety. You need to get her to the vet and have her thoroughly checked. If it's fleas or another parasite, she needs prescription medication (don't use over the counter stuff, as it is often toxic). If it's anxiety, then your vet can help you come up with a plan for helping her manage it.